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280 lines
7.2 KiB
280 lines
7.2 KiB
#! /usr/bin/env crystal run
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require "colorize"
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require "./readline"
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require "./reader"
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require "./printer"
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require "./types"
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require "./env"
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require "./core"
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require "./error"
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# Note:
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# Employed downcase names because Crystal prohibits uppercase names for methods
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def func_of(env, binds, body)
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-> (args : Array(Mal::Type)) {
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new_env = Mal::Env.new(env, binds, args)
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eval(body, new_env)
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} as Mal::Func
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end
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def eval_ast(ast, env)
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return ast.map{|n| eval(n, env) as Mal::Type} if ast.is_a? Array
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val = ast.unwrap
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Mal::Type.new case val
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when Mal::Symbol
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if e = env.get(val.str)
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e
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else
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eval_error "'#{val.str}' not found"
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end
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when Mal::List
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val.each_with_object(Mal::List.new){|n, l| l << eval(n, env)}
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when Mal::Vector
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val.each_with_object(Mal::Vector.new){|n, l| l << eval(n, env)}
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when Mal::HashMap
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new_map = Mal::HashMap.new
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val.each{|k, v| new_map[k] = eval(v, env)}
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new_map
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else
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val
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end
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end
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def read(str)
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read_str str
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end
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macro pair?(list)
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{{list}}.is_a?(Array) && !{{list}}.empty?
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end
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def quasiquote(ast)
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list = ast.unwrap
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unless pair?(list)
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return Mal::Type.new(
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Mal::List.new << gen_type(Mal::Symbol, "quote") << ast
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)
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end
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head = list.first.unwrap
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case
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# ("unquote" ...)
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when head.is_a?(Mal::Symbol) && head.str == "unquote"
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list[1]
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# (("splice-unquote" ...) ...)
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when pair?(head) && (arg0 = head.first.unwrap).is_a?(Mal::Symbol) && arg0.str == "splice-unquote"
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tail = Mal::Type.new list[1..-1].to_mal
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Mal::Type.new(
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Mal::List.new << gen_type(Mal::Symbol, "concat") << head[1] << quasiquote(tail)
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)
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else
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tail = Mal::Type.new list[1..-1].to_mal
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Mal::Type.new(
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Mal::List.new << gen_type(Mal::Symbol, "cons") << quasiquote(list.first) << quasiquote(tail)
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)
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end
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end
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def macro_call?(ast, env)
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list = ast.unwrap
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return false unless list.is_a? Mal::List
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return false if list.empty?
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sym = list.first.unwrap
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return false unless sym.is_a? Mal::Symbol
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func = env.find(sym.str).try(&.data[sym.str])
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return false unless func && func.macro?
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true
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end
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def macroexpand(ast, env)
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while macro_call?(ast, env)
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# Already checked in macro_call?
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list = ast.unwrap as Mal::List
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func_sym = list[0].unwrap as Mal::Symbol
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func = env.get(func_sym.str).unwrap
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case func
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when Mal::Func
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ast = func.call(list[1..-1])
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when Mal::Closure
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ast = func.fn.call(list[1..-1])
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else
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eval_error "macro '#{func_sym.str}' must be function: #{ast}"
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end
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end
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ast
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end
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macro invoke_list(l, env)
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f = eval({{l}}.first, {{env}}).unwrap
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args = eval_ast({{l}}[1..-1], {{env}}) as Array
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case f
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when Mal::Closure
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ast = f.ast
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{{env}} = Mal::Env.new(f.env, f.params, args)
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next # TCO
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when Mal::Func
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return f.call args
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else
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eval_error "expected function as the first argument: #{f}"
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end
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end
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def debug(ast)
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puts print(ast).colorize.red
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end
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def eval(ast, env)
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# 'next' in 'do...end' has a bug in crystal 0.7.1
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# https://github.com/manastech/crystal/issues/659
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while true
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return eval_ast(ast, env) unless ast.unwrap.is_a? Mal::List
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ast = macroexpand(ast, env)
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list = ast.unwrap
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return ast unless list.is_a? Mal::List
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return ast if list.empty?
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head = list.first.unwrap
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return invoke_list(list, env) unless head.is_a? Mal::Symbol
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return Mal::Type.new case head.str
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when "def!"
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eval_error "wrong number of argument for 'def!'" unless list.size == 3
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a1 = list[1].unwrap
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eval_error "1st argument of 'def!' must be symbol: #{a1}" unless a1.is_a? Mal::Symbol
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env.set(a1.str, eval(list[2], env))
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when "let*"
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eval_error "wrong number of argument for 'def!'" unless list.size == 3
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bindings = list[1].unwrap
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eval_error "1st argument of 'let*' must be list or vector" unless bindings.is_a? Array
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eval_error "size of binding list must be even" unless bindings.size.even?
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new_env = Mal::Env.new env
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bindings.each_slice(2) do |binding|
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key, value = binding
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name = key.unwrap
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eval_error "name of binding must be specified as symbol #{name}" unless name.is_a? Mal::Symbol
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new_env.set(name.str, eval(value, new_env))
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end
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ast, env = list[2], new_env
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next # TCO
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when "do"
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if list.empty?
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ast = Mal::Type.new nil
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next
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end
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eval_ast(list[1..-2].to_mal, env)
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ast = list.last
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next # TCO
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when "if"
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ast = unless eval(list[1], env).unwrap
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list.size >= 4 ? list[3] : Mal::Type.new(nil)
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else
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list[2]
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end
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next # TCO
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when "fn*"
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params = list[1].unwrap
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unless params.is_a? Array
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eval_error "'fn*' parameters must be list or vector: #{params}"
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end
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Mal::Closure.new(list[2], params, env, func_of(env, params, list[2]))
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when "quote"
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list[1]
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when "quasiquote"
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ast = quasiquote list[1]
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next # TCO
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when "defmacro!"
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eval_error "wrong number of argument for 'defmacro!'" unless list.size == 3
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a1 = list[1].unwrap
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eval_error "1st argument of 'defmacro!' must be symbol: #{a1}" unless a1.is_a? Mal::Symbol
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env.set(a1.str, eval(list[2], env).tap{|n| n.is_macro = true})
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when "macroexpand"
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macroexpand(list[1], env)
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when "try*"
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catch_list = list[2].unwrap
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return eval(list[1], env) unless catch_list.is_a? Mal::List
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catch_head = catch_list.first.unwrap
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return eval(list[1], env) unless catch_head.is_a? Mal::Symbol
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return eval(list[1], env) unless catch_head.str == "catch*"
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begin
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eval(list[1], env)
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rescue e : Mal::RuntimeException
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new_env = Mal::Env.new(env, [catch_list[1]], [e.thrown])
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eval(catch_list[2], new_env)
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rescue e
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new_env = Mal::Env.new(env, [catch_list[1]], [Mal::Type.new e.message])
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eval(catch_list[2], new_env)
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end
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else
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invoke_list(list, env)
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end
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end
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end
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def print(result)
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pr_str(result, true)
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end
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def rep(str)
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print(eval(read(str), $repl_env))
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end
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$repl_env = Mal::Env.new nil
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Mal::NS.each{|k,v| $repl_env.set(k, Mal::Type.new(v))}
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$repl_env.set("eval", Mal::Type.new -> (args: Array(Mal::Type)){ eval(args[0], $repl_env) })
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rep "(def! not (fn* (a) (if a false true)))"
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rep "(def! load-file (fn* (f) (eval (read-string (str \"(do \" (slurp f) \")\")))))"
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rep "(defmacro! cond (fn* (& xs) (if (> (count xs) 0) (list 'if (first xs) (if (> (count xs) 1) (nth xs 1) (throw \"odd number of forms to cond\")) (cons 'cond (rest (rest xs)))))))"
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rep "(defmacro! or (fn* (& xs) (if (empty? xs) nil (if (= 1 (count xs)) (first xs) `(let* (or_FIXME ~(first xs)) (if or_FIXME or_FIXME (or ~@(rest xs))))))))"
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rep("(def! *host-language* \"crystal\")")
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$argv = Mal::List.new
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$repl_env.set("*ARGV*", Mal::Type.new $argv)
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unless ARGV.empty?
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if ARGV.size > 1
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ARGV[1..-1].each do |a|
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$argv << Mal::Type.new(a)
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end
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end
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begin
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rep "(load-file \"#{ARGV[0]}\")"
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rescue e
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STDERR.puts e
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end
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exit
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end
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rep("(println (str \"Mal [\" *host-language* \"]\"))")
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while line = my_readline("user> ")
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begin
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puts rep(line)
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rescue e
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STDERR.puts e
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end
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end
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